Summary On 02 August 1996, the tug WELDWOOD19 was pushing a flat-topped barge with two tandem-axle dump trucks on deck. The tugmaster noticed that the barge's draught had increased and that the barge was developing a starboard list. He repositioned the trucks on the deck to counter the list and decided to turn the barge to starboard toward the shore. While making this turn, the barge developed a steadily increasing port list before striking an underwater rock and coming to a stop. The port list increased to the point where the trucks and their cargo of asphalt slid over the port side as the barge sank in about five metres of water. The tugmaster sustained a minor injury, and the asphalt caused some pollution. Ce rapport est galement disponible en franais. Other Factual Information Particulars of the Vessels Description of the Barge The barge is a converted dump/dredging barge. A flat, bare steel plate forms the surface of the main deck. A loading/unloading ramp is at the forward end. The main deck is not bounded by safety rails nor is it fitted with cargo securing devices. The welded connection of the deck to the side shell plating was neither continuous nor watertight. The main deck plating was extensively corroded, perforated and holed. At the forward end of the barge on the starboard side, approximately 0.5 m below the hinged loading ramp, a welded seam was split, such that daylight could be seen through it from the interior of the barge. The barge is not subdivided longitudinally or transversally. However, near each end of the barge, the internal transverse bottom framing structure is about 1 m high. Consequently, any water in the barge above 1 m in depth can flow freely throughout the hull. Any water below this level is also free to flow throughout the main parallel body of the barge. It was reported that water, which accumulated in the barge after it had lain idle or which was shipped when underway, was occasionally pumped out using a 5 HP gasoline portable pump located on the main deck. Its flexible two-inch diameter suction was led through six-inch high, five-inch diameter, open-topped stand pipes at each end of the barge. The barge, which has no crew, is not equipped with propulsion machinery, boilers or compressors and does not carry passengers. There is no regulatory requirement for it to be inspected or certificated by Transport Canada (TC) Marine Safety. As the barge does not normally carry a crew, there is no regulatory requirement for life-saving equipment to be carried on board. The Voyage The tug/barge, accompanied by a work boat, was making its second trip of the day from Honey Harbour to a construction site. On the deck of the barge, were two dump trucks loaded with asphalt, reportedly giving the barge estimated freeboards of about 0.6 m forward and 0.5 m aft. The trucks were not secured to the deck for the 45-minute trip nor were their wheels chocked. It was reported that the barge was upright and its internal spaces were dry on departure. At 1545[1], the mate was operating the WELDWOOD19 which was pushing the barge at a speed of about five or six knots. The surface of the lake was choppy due to the wake of passing pleasure craft. At that time, the tug/barge had travelled about three-quarters of the distance to its destination. The tugmaster noticed that the barge's freeboard was decreasing and that the barge was developing a starboard list. He did not consider starting the bilge pump at this time. During the passage, the tugmaster repositioned the trucks on the deck several times to counter the list. The starboard truck and its load of asphalt (24 tons total) was repositioned closer to the asphalt-laden truck on the port side (22 tons total). Course was altered to starboard toward the shore about 200 m off to starboard. The barge then developed a list to port which steadily increased until the deck edge was almost awash. Within two minutes of the start of the turn, the tugmaster started the gasoline-powered portable bilge pump but it did not keep up with the continuous ingress of water. The tugmaster then instructed the truck drivers, who were travelling on the barge, to disembark from the barge to the stand-by work boat. The barge then struck an underwater rock and came to a stop approximately 10 m from shore. The starboard dump truck slid across the deck into the truck on the port side, and the port list increased to the point where, at 1615, the barge spilled both trucks and their cargo of asphalt into four to five metres of water. The partially flooded barge continued to downflood until reserve buoyancy was lost. It then settled on the bottom, deck side up. The system of making the tug and barge fast to each other did not incorporate a quick-release mechanism. The barge was chained to the tug in the pushing mode. When the barge was heeled over and sinking, the tugmaster had difficulty disconnecting the chains, and in the process he suffered a minor back injury. The tugmaster had approximately 10 years' experience operating small barges and tugs. He had held a Master, Small Craft certificate which had expired about a year before the occurrence. The syllabus for the oral and practical examination required for this certificate does not require an in-depth understanding of vessel stability in general or of the effect of free-surface liquids in particular. The barge was normally pushed at a speed of about four knots by a less powerful tug.